Writing instrument construction

ABSTRACT

A POCKET-TYPE WRITING INSTRUMENT CONSTRUCTION INCLUDING A REMOVABLE REPLACEABLE VAPOR-PROOF, IMPERMEABLE CARTRIDGE OR HOUSING MEANS HAVING AN AIR VENT ADJACENT A WRITING TIP MEMBER OF WICK-LIKE TYPE AND PRESENTING A YIELDABLE SEALING SURFACE TO INTERNAL SURFACES ON AN INSTRUMENT BODY MEANS TO PROVIDE AN AIR SEAL BETWEEN SAID CARTRIDGE AND BODY MEANS, AND FURTHER SEAL MEANS BETWEEN SAID BODY MEANS AND A WRITING INSTRUMENT CAP COVER MEANS FOR THE WRITING TIP WHEREBY EVAPORATION AND LOSS OF   VAPORIZABLE INK COMPONENTS DURING STORAGE OR NON-USE OF THE WRITING INSTRUMENT IS INHIBITED AND THE OVERALL WRITING LIFE OF THE INSTRUMENT IS ENHANCED.

s. L. MALM a-r m. 3,554,658

Jam-12, 1971 WRITING INSTRUMENT CONSTRUCTION 3 Sheets-Sheet l v r l llllll lllliln 1 E m\ .mwn

' INVENTORS. CURTIS L. MALM .HENRY J. LOEWENTHAL 6%, PM 4smm ATTORNEYS.

I c. L. MALM EI'AL WRITING INSTRUMENT CONSTRUCTION I Fild June 1 :9 9

Jan. 12,1971

3 Sheets-Sheet 2 j lNQsm'oras. CURTIS L. MALM HENRY J.- LOEWENTHAL 60 pm 5m A-r-ro RN EYS.

c; 1.. MALM ETAL WRITING INSTRUMENT CONSTRUCTION Jail. 12, 1971 3 Sheets-Sheet 5 Eiid' June 18/1969 INVENTORS. 'cumws I... MALM hm kQpwm .v

L s M Mm m R E .8. O w W MWP L. J

3,554,658 WRITING INSTRUMENT CONSTRUCTION Curtis L. Malm, Norwalk, and Henry J. Loewenthal,

Woodland Hills, Califi, assignors to The Gillette Company, Santa Monica, Calif., a corporation of Delaware Filed June 18, 1969, Ser. No. 834,461 Int. Cl. B43k 8/00 US. Cl. 401-199 9 Claims ABSTRACT on HE DISCLOSURE A pocket-type writing instrument construction including a removable replaceable vapor-proof, impermeable cartridge or housing means having an air vent adjacent a writing tip member, of wick-like type and presenting a yieldable sealing surface to internal surfaces on an instrument body means to provide an air seal between said cartridge and body means, and further seal means between said body means and a writing instrument cap cover means for the writing tip whereby evaporation and loss of vaporizable ink components during storage or non-use of the writing instrument is inhibited and the overall writing life of the instrument is enhanced.

The commercial acceptance of pens (writing instruments) which utilize porous composition writing or marking tips (such stips having a plurality of capillary channels which feed an ink from a reservoir to the writing end of such tip) presents av number of unanticipated problems. Theoretically, any porous wick of reasonable length can have one end put into an ink supply source and eventually the ink will reach the free end of such wick whereby such free end could be used for marking. But such arrangement is not practical: a user does not want to go to the trouble of combining such elements immediately prior to every instance of contemplated use; instead, a completely preassembled writing instrument should be capable of being shipped and stored for a long time and be capable of immediate writing use after such storage. If such theoretical assemblyof porous wick and ink supply is allowed to stand for a period of 48 hours or more, during which ink continues to evaporate from the wick, the ink supply becomes reduced or even depleted and drying of the free end of the wick impair or even destroy the initial writing United States Patent ability. Means must be provided for admitting air into an ink reservoir to replace ink use in" writing, but unrestrained access of air accelerates evaporation of vaporizable ink components and reduces the work life of a writing instrument. These contrasting and conflicting requirements and properties have presented problems, their solution constitutes the present invention.

Generally stated, the present invention relates to a pocket-type writing instrument embodying a sealed, virtually vapor-proof ink reservoir housing containing a porous mass whose interstices contain acharge of ink, a

'James OSullivan and Daniel WilliantSeregely is well suited) having one end in feeding contact with the ink carrying mass of the reservoir and the other end adapted for use as a writing end.The reservoir is contained and held in a barrel provided with a forwardly opening axial Patented Jan. 12, 1971 rene base material. The barrel is also preferably provided with a removable cap containing an internal resilient tip cover which provides an air-tight seal with the barrel and protects the writing end of the writing tip when the instrument is not in use.

An object of this invention therefore is to disclose and provide a writing instrument construction so arranged that characteristics of writing readiness and long writing life are enhanced.

An object of the invention is to disclose and provide a writing instrument construction which obviates and substantially eliminates vapor loss at a writing tip member of wick-type during period of non-use or of storage and prevents dry-out at the writing tip member.

Another object of the invention is to disclose and provide a writing instrument construction wherein a replaceable cartridge means having a wick-type writing point is constructed and arranged to provide an effective airtight seal with a cartridge cap for storage purposes and a similar effective seal with internal surfaces of a barrel of a writing instrument body means, the writing instrument including a writing instrument cap constructed and arranged to provide an effective airtight seal with external surfaces of the barrel when the writing instrument is not m use.

Another object of the invention is to disclose and provide a writing instrument construction wherein a cartridge or ink reservoir housing is made of metal and provided with a plastic writing tip holder member, the holder member providing air vent means communicating with an air passageway in a porous ink mass carried within the hous ing, the cartridge in storage being provided with a cap means sealing against the holder member for sealing the air vent means.

A further object of the invention is to disclose and provide a Writing instrument construction including novel sealing means operable between a vapor proof ink reservoir cartridge means and a cartridge cap as well as between the cartridge means and a barrel of a writing instrument body means, and operable to maintain an effective seal under varying temperature and pressure changes acting on the Writing instrument during storage and during periods of non-use.

A still further object of the invention is to disclose and provide a novel arrangement of a cartridge means having a porous writing tip member with a writing instrument body means whereby the porous writing tip member is protected and is stored within a virtually airtight seal chamber when the instrument is not in use.

A specific object of the invention is to disclose and provide means for holding a writing tip member of porous wick type wherein a yieldable plastic surface is provided for airtight sealing engagement with a plastic cartridge cap or a plastic barrel of a writing instrument body means.

Another specific object of the invention is to disclose and provide a writing instrument having a porous wicktype writing member of generally rigid form and projecting from the end of a holder member and wherein means are provided for supporting the projecting portion of the writing tip member during storage in an airtight chamber.

Another object of the invention is to provide a construction wherein air communication is provided in novel manner between the back of a porous ink mass in a cartr'idge and the writing tip receiving chamber of a pen cap means to elim-inate and prevent ink leakage when the writing construction is subjected to temperature varia tions.

Other advantages and objects of the present invention will be readily apparent from the following description of the drawings in which an exemplary embodiment of the invention is shown.

In the drawings:

FIG. 1 is a side elevational view, partly in section, of a writing cartridge means and cap therefor for a writing instrument embodying this invention.

FIG. 2 is a transverse sectional view taken in the plane indicated by line IIII of FIG. 1.

FIG. 3 is a transverse sectional view taken in the plane indicated by line III-III of FIG. 1.

FIG. 4 is a transverse sectional view taken in the plane indicated by line IVIV of FIG. 1.

FIG. 5 is a longitudinal sectional view of the point holder shown in the cartridge means of FIG. 1.

FIG. 6 is a transverse sectional view taken in the plane indicated by line VIVI of FIG. 5.

FIG. 7 is a fragmentary side view of the back or rear end portion of the holder shown in FIG. 5.

FIG. 8 is a longitudinal sectional view of a writing instrument with the cartridge means of FIG. 1, the sectional view being taken in a plane passing through the axis of the writing instrument.

FIG. 9 is an enlarged fragmentary sectional view taken in a plane similar to FIG. 8 and showing more clearly the sealing arrangement between the barrel of the writing instrument body means, the cartridge means, and the writing instrument cap means.

FIG. 10 is an enlarged sectional view taken in the plane indicated by line XX of FIG. 8.

FIG. 11 is an enlarged fragmentary sectional view taken in the transverse plane indicated by line XIXI of FIG. 9.

A writing instrument embodying this invention is generally indicated at 15, FIG. 8, and may comprise a cylindrical writing cartridge means 16 adapted to be held and fitted within a pen body means including a forward barrel 17 and a rear plume means 1 8 threadedly connected thereto, the barrel 17 being provided with a removable pen cap means 19. When cap 19 is in assembled closed relation with the barrel 17, a rigid porous writing tip member 20 of cartridge means 16 is in virtually airtight sealed relation with relation to cap 19, barrel 17, and cartridge 16. In writing position with pen cap 19 removed, tip member 20 is exposed and operable; air vent means in the cartridge means permitting ink flow to the writing tip member. Cartridge means 16 is removable from the pen barrel for replacement and is maintained in airtight sealed relation during storage, that is, outside the pen body means by the provision of a disposable cartridge cap means 14, FIG. 1. The cartridge means alone may be used as a writing instrument although in this embodiment of the invention use of the cartridge with a pen body means is preferable.

The writing cartridge means 16, FIG. 1, may comprise an elongated cylindrical housing or metal casing 24 having a back opening 25 and a front opening 26. The casing 24 may be of generally uniform diameter for a major portion of its length. Back opening 25 may be suitably closed by an elongated back plug 27 provided with a suitable taper and having a back end face 28. Back plug 27 also includes an annular rib portion 29 providing a shoulder 30 for seating of the back edge of casing 24, the back end portion of casing 24 being spun over and about the cylindrical portion 31 of back plug 27 to retain and tightly fit the back plug in opening 25. rRelatively short cylindrical portion 31 which lies forwardly of shoulder 29 terminates in a forwardly reduced portion 32 having surfaces spaced from the internal surfaces of casing 24. Portion 32 may be provided with diametrically opposed notches 33 providing communication between the annular space around portion 32 and the top end face 34 of an ink mass 36.

Ink mass 36 may be made of a suitable ink absorbent material and is charged with a suitable ink composition. The porous ink mass extends to a forwardly and inwardly tapered portion 38 of casing 24, the ink mass having embedded therein an open ended tube 39 of suitable plastic composition unaffected by the ink charged porous mass 4 for providing an air passageway between opposite ends of the ink mass. Open ended tube 39 may be placed in the ink charged mass 36 during formation of the ink mass, and preferably is disposed along an axis spaced from the axis of the ink mass which coincides with the axis of casing 24.

The tapered forward portion 38 of casing 24 terminates in a generally cylindrical forward section 40 which receives and frictionally engages and holds a writing point holder means 42. The front edge faces of the forward section 40 of the casing 24 abut and seat against a shoulder at 43 of point holder means 42, the forward section 40 being spun over so as to tightly engage and 'be sealed against the external cylindrical surfaces of point holder means 42 at and rearwardly of the shoulder 43.

Point holder means 42 may comprise an integral plastic body of suitable material, such as polypropylene, having a front cylindrical end portion 44 adapted to receive and hold writing tip member 20 as at 45. To prevent longitudinal movement of tip member 20 relative to point holder means 42 a diametrically disposed wire pin or stake 46 may be passed through portion 44 and tip member 20.

Point holder means 42 may also comprise a central portion 48 of relatively thick material section and provided with a suitable polygonal through opening 49, FIGS. 5 and 6, adapted to provide a plurality of spaced longitudinally extending grooves 50 forming air passages. The forward ends of grooves 50 terminate in vent ports 51 opening between intermediate portion 48 and front portion 44. In this example three vent ports 51 are provided.

Intermediate portion 48 is also formed with a slightly diametrically enlarged forwardly projecting thin-walled annular flange or rib portion 53 defining with the adjacent outer cylindrical surface of front portion 44, an annular recess 54 into which ports 51 open. Annular flange portion 53 provides an external generally cylindrical surface 55 which serves as a sealing surface as later described and which is resilient and yieldable.

Intermediate portion 48 of holder means 42 merges with a rear portion 57 of generally cylindrical configuration and having a slightly reduced outer diameter as best seen in FIG. 7. Back portion 57 may be provided with rearwardly opening slots 58 to provide communication between the interior of point holder means 42 to annular space 60 provided between tapered portion 38 of casing 24 and the back portion 57 of the point holder. Annular space 60 communicates with the forward open end 61 of vent tube 39 carried in ink mass 36.

Writing tip member 20 may comprise a relatively rigid elongated member, preferably made of synthetic fibers such as nylon filaments arranged in generally parallel relation and discontinuously bonded together to provide a multiplicity of capillary ink channels which communicate with each other from one end of writing tip member 20 to the other end thereof. An example of such a writing tip member is described in copending application Ser. No. 560,405, filed June 27, 1966. Tip member 20 may comprise an elongated generally cylindrical tip body 64 having a diameter to provide a close fit at 45 with front end portion 44 of holder means 42. Opposite ends of tip body 64 may be similarly shaped and each end may include a tapered generally frusto-conical portion 65 and a pointed tip portion 66 at the extremity of tapered portion 65. Inasmuch as both ends of writing tip body 20 are similarly shaped, one or the other of said ends may be inserted in the bore at 45 and writing tip member 20 urged or pushed through the bore until the inner end of member 20 is forced into, embedded, or penetrates into the bottom or lower portion of ink mass 36 as at 67 so that ink from mass 36 will feed by capillary action into, through and along tip body 64.

For storage purposes the cartridge means 16 may be provided with a disposable cartridge cap means 14 which maybe of, suitable impermeable vapor proof material and of selected length to cover the writing tip member 20. and the forward. section of the cartridge means 24. Cap means 14' may comprise an elongated generally tapered hollow cap body 70 having a closed end wall 71 and an opposite opening 72 adapted to receive the front end portion of casing 24. Extending from end wall 71 may be a plurality; of circularly spaced longitudinal ribs 7..having parallel faces 74 angularly spaced apart to slidablyengage the external surface of cylindrical portion 44 of the point holder means. Such engagement together with the sealing engagement of cap 14 with the holder means (later described) stabilizes and maintains axial alignment of the cap with the cartiidge casing and writing tip member. Contact of the tip member with the cap is prevented and unwanted wicking action which may occur when the tip touches the cap is avoided. Spaced from the outermost ends of ribs 73, body 70 provides an internal stop shoulder 75 for limiting longitudinal movement of cartridge cap means 14 on the cartridge means 24 by abutment with the forward edge face of annular forwardly directed rib 53 of point holder means 42. Longitudinally outwardly of shoulder 75, the internal surface of body 70 may be provided with a relatively short cylindrical internal surface portion 76 and an outwardly flared surface portion 77 terminating in an elongated cylindrical surface portion 78. Thus when cap means 114 is inserted on the cartridge means 24, sealing surface 55 of point holder means 42 is urged into airtight sealing relationship asat 79 with internal surface portion 76 77 and the ridge-like annular junction betwen surface portion 77 and cylindrical portion 76. Outwardly of internal cylindrical surface portion 78, body 70 may :be

further; enlarged to'the diameter of opening 7-2 so as to permit opening 72 to readily receive the forward tapered metal section 38 of casing 24. Capmeans 14 thus pro- .vides atight 'line-type seal between two bodies of impervious plastic material, the seal. being relatively unaflecte'd ;by temperature and pressure changes.

Cartridge; cap means 14,"point holder means 42, and back plug 27 are preferably made of a readily moldable plastic composition material having apor-proof impermeable characteristics, such materials including polyolefinic, polypropylene and polyethylene compositions. Such material preferably has similar temperature and pressure response characteristics. I

f Cartridge means ---16- 'is preferably assembled with a writing instrument or pen body means 15 which may comprise a barrel 17 anda plume member 18. In FIGS. 8-10; the assembly of3such a cartridge means 16 within the body means15 is shown, details of the cartridge means being omitted for purposes of clarity.

Plume member 18 maybe ofany suitable length and includes a selected; tapered cross-section progressively decreasing towards the top ortupper ,end of plume member 18 whichincludes an end wall 81 having a port 8-2 therein. The top endportion of plume member 18 provides a spring chamber 83*withinjwhich may be seated a coi1'spring84 having end;-turns .'85 ,adjacent wall 81 in frictional engagement at 86 with the internal surfaces of chamber 83 toretain spring 84 therein. Chamber 83 may include aplurality of longitudinal internal ribs 87 having end faces 88 serving as a limit stop for the end wall of the backplug 27 of the cartfidge means. The open end '89 of plume member 18 may receive top end portion 90 of the barrel 17 for threaded connection thereto asat 91. a a

The barrel 17 may include at top end portion 90, a suitable annular..surface recess 92. adapted to support and hold a metal band,93 for abutment with edge face of plume 18 andfor seating of the writing, instrument cap means 19 as later described.

Barrelf lTmay be suitably tapered toward its writing point endland is provided with radially inwardly directed thickened end portion 95 provided with a'plurality of longitudinally extending slots 96,'the thickened portion 95 6 defining an axial aperture 97. Fitted within aperture 97 may be a suitable insert ferrule type member 98 of metal material and having a back annular flange 99 seated on internal back faces of thickened portion 95. Insert 98 extends forwardly of end portion for reception within and frictional connection to a generally cylindrical barrel tip member 100 of suitable material, such as metal. Member 100 has an axial aperture 101 to receive, hold, and support a forward end portion of writing tip member 20 when the cartridge means is assembled with the barrel.

The internal configuration of the barrel 17 rearwardly of insert 98 includes internal cylindrical surface 103 for reception of the forward end portion 44 of point holder means 42. Cylindrical surface 103 terminates in an annular internal rearwardly directed shoulder 104 Which merges with an internal progressively radially outwardly increasing internal surface portion 105 of the barrel. Internal surface portion 106 adjacent shoulder 104 is pro vided with an internal diameter slightly smaller than the external diameter of forwardly directed flange 53 of the point holder means 42 so that surface 55 of said flange will frictionally and sealingly engage surface portion 106 on the barrel to provide an airtight seal, air passing from port 82 forwardly along internal surfaces of the plume and barrel members to such sealing area. Coil spring 84 urges cartridges means 16 forwardly into and maintains such tight sealing engagement, flange 53 resiliently yieldably providing pressure contact with the barrel.

The barrel and plume members may be made of a readily moldable plastic, composition material; the barrel member being made of an impermeable plastic resinous composition preferably having good appearance and low vapor transmission characteristics, as for example polyolefin, styrene base materials, and acrylics. The plume member may be made of any suitable plastic, such as a mate rial such as cellulosic propionate or styrene composition having acceptable and pleasing colors and readily worked and molded into suitable shapes and configurations.

'Cap means 19 of writing instrument 15 comprises an outer cap member 110 having a wall 111 of suitable configuration provided with an open end portion carrying a metal ring 112 slidable over band 93 when cap member 110 is placed over the barrel when the instrument is not in use. Metal ring 112 frictionally slidably engages band 93, a plurality of spaced dimples 113 on barrel 17 urging band 93 into frictional contact with metal ring 112. The opposite end of cap means 110 may be provided with an axial port 115 and a suitable pen clip assembly 116 mounted upon the cap member in well known manner.

Within pen cap means 19 may be carried an impermeable plastic tip cover member 117, said member having a closed end portion 118 provided with an exterior annular recess 119 adapted to interlock with an internal radially inwardly extending annular rib 120 provided on cap means 19 inwardly of opening 115. The tip cover member 117 is provided with a generally cylindrical wall 121 which is of varying annular cross-section and flares conically outward between end wall 118 and open end 122. Wall 121 may be provided with a thin annular material section at 123 permitting flexing or hinge-like outward expansion of open end portion 124. of wall 121. End portion 124 may have a radially inwardly directed and thick-. ened wall portion 125 providing a sealing surface at 126 defined by an internal annular recess 127 which provides a thin wall section extending toward open end 122. Wall 121 at opening 122 may include a thickened wall section 128 having an inwardly directed edge 129 Which may contact barrel 17, although such contact is not relied upon for an air sealing purpose. The sealing surface 126 of thickened wall portion 125 tightly resiliently and frictionally engages the opposed external surface portion 130 on the front portion of the barrel 17, the surface engagement being held under pressure by positioning cap means 19 on the barrel into closed position and by the resilient flexibility of sealing surface 126 of the tip cover member 117. Tip cover member 117 may be made of suitable impermeable, flexible resilient plastic compositions such as polyethylene, polypropylene and the like.

Writing cartridge means 16 may be readily replaced by unthreading the plume and barrel members of the writing instrument and removing the cartridge means by withdrawing from the separated barrel and plume members. A new writing cartridge means (with cap removed) may be readily inserted into the barrel section, writing tip member being aligned with and pushed through the insert member 98 and barrel tip member 100. The plume member may then be sleeved over the rear portion of the cartridge means and threaded on the barrel member 19. As the plume member is tightened, it will be apparent that the spring means 84 together with the stop shoulder at 88 urges the cartridge means forwardly so that the sealing surface 55 on flange 53 of the point holder means is moved into sliding sealing contact with the internal surface 106 of the barrel.

When so assembled with the barrel and plume members and with the cap 19 removed, air venting of the porous ink mass in the cartridge means is provided by the air vent openings 51 in the point holder means 42, the air communicating through the point holder means and vent tube 39 to the back end of the porous ink mass at the space provided between the rear plug 27 and the back end face of the ink mass. It should be noted that plastic tube 39 may include a suitable extruded tube of plastic composition which may be wrapped in a covering of plastic material such as cellophane, which is resistant to the ink carried by the porous mass.

It will thus be apparent that a cartridge means 16 having a metal casing and impermeable back plug and front point holder means provides a vapor-proof construction which is vented only through the point holder means. The resilient yieldable sealing surface 55 on the forwardly directed flange of the point holder means provides a sealing surface which is cooperable with a cartridge cap for sealing during storage periods and which is also cooperable with internal surfaces on a barrel for sealing when the cartridge is assembled with a writing instrument body means. When assembled with a pen body means, the cap means therefor provides an impermeable internal sealing surface which slidably frictionally engages the external surface of the barrel sealing the writing tip member and cartridge means when the writing instrument is not used. The particular sealing arrangement described above provides sealing surfaces in sealing contact, the surfaces being formed on plastic composition material having virtually the same response characteristic to temperature and pressure so that differences in contraction and expansion of the materials is minimized and insignificant so as to prevent creeping or displacement of one member with respect to the other as may be caused by differences in temperatures and pressures occurring in the course of a day.

The sealing arrangement described above provides effective means for isolating the porous writing tip member from outside or ambient air and also provides a closed sealed construction when a cartridge cap or pen cap is fitted over the writing tip member. It should be noted that under such conditions air communication within the closed system is provided between the back of the ink mass, through the air tube, slots, grooves, and vent ports 51 in the writing tip holding means, and when the cartridge cap is in closed position, through the space between ribs 73 to the writing tip chamber provided by the cap. When a pen cap is in closed position on the barrel member, air communication is further provided by the slots 96 which lead to the chamber provided by the writing tip cover member 117. Maintenance of such air communication between the back of the cartridge and the writing tip member prevents and eliminates leaking of ink during temperature changes, the leaking being caused by pressure d fierentials caused by such temperature variations.

Thus, the above described construction of the cartridge means and writing instrument body means prevents evaporation of vaporizable ink components during storage, maintains the writing tip in wet undried condition, and provides a writing tip which is ready for writing when used.

It will be understood that while the described example of the present invention is made with respect to a porous writing tip and an ink absorbent mass, the air sealing features of the construction may be readily adapted to other pen body and cartridge constructions. Changes and modifications coming within the scope of the appended claims are embraced thereby.

We claim:

1. In a writing instrument construction, the combination of:

an impermeable elongated cylindrical and replaceable cartridge housing closed at one end and providing an ink chamber;

a porous mass containing an ink charge positioned in said ink chamber;

air vent means extending through said mass to communicate with opposite ends of said ink mass;

a writing tip member rigid relative to said mass and having one end in feeding contact with said mass and having its other end projecting from said other end of said housing for use as a writing point;

means received within said other end of said housing for holding the writing tip member;

said holding means including air vent passageways and an outer resilient yieldable circumferential sealing surface forwardly of said housing; and

means removably associated with and receiving therewithin said holding means for isolating said air vent passageways from atmosphere and including an internal sealing surface cooperable with said yieldable circumferential sealing surface on said holding means for effecting a seal.

2. In a construction as stated in claim 1 wherein said isolating means includes a disposable cartridge cap member provided with said internal sealing surface, and

a stop means adjacent said internal sealing surface for limiting relative longitudinal movement of said cap member and said holding means.

3. A writing instrument construction as stated in claim 2 wherein:

said holding means is made of an impervious plastic material,

said holding means including a forwardly directed flange providing said outer sealing surface and a forwardly directed edge face for abutment with said stopmeans.

4. A Writing instrument construction as stated in claim 2 wherein said disposable cartridge cap member includes circumferentially spaced internal longitudinally extending ribs slidably engageable with said holding means at a location spaced from said sealing surfaces for maintaining axial alignment and stability of said cap member.

5. A writing instrument construction as stated in claim 1 wherein said internal sealing surface on said isolating means is provided on a hollow barrel member of a writing instrument body means adapted to replaceably receive and hold the cartridge housing.

6. A writing instrument construction as stated in claim 5 including:

a writing instrument cap means provided with a generally conical internal writing tip cover member;

said conical tip cover member having internal resilient yieldable surfaces for sealing engagement with external surfaces on said barrel member forwardly of said internal sealing surfaces on said barrel member.

7. A writing instrument construction as stated in claim 6 wherein said conical internal writing tip cover member includes a closed end having a connection to said writing instrument cap means, and

9 10 a generally conical Wall extending from said closed end sealing surface means between said writing tip cover and having a reduced material section intermediate member and an external surface portion of said inits ends providing yieldability to the internal sealing strument body means, and surfaces on said tip cover member. sealing surface means between internal surfaces on said 8. In a Writing instrument adapted to maintain ready body means and said writing tip holding means,

writing characteristics and to prevent loss of vaporizable 5 each of said sealing surface means including resilient ink components during periods of storage and non-writing sealing surface portions of impermeable plastic mause, the provision of: terial yieldable relative to said surface portions on a hollow Writing instrument body means provided with said instrument body means.

a pen cap means having an internal impermeable 9. An instrument as stated in claim 8 wherein said air Writing tip cover member therein; vent means and air passageway means in said body means an impermeable cartridge means removably carried provide air communication between the back of said porwithin said body means and including ous mass and the writing tip member in said cap means.

a cartridge housing closed at one end and open at the other d, 15 References Cited writing tip holding means carried in said open end of UNITED STATES PATENTS said housing in rigid relationship therewith,

a writing tip member projecting from said holding 2,302,450 8/ 1957 Witt bert 23 means and extending into said cartridge housing 3, 3/1962 ROSBIlthal 01199 means, 20 3,121,906 2/1964 Hulsh 401-202 an ink carrying porous mass in said housing means in 3,446,563 5/1969 Burnham 401-199 ink feeding contact with said writing tip member, and 3,468,613 9/ 1969 Strickler 401-199 air vent means provided in said holding member and in said mass; LAWRENCE CHARLES, Primary Exammer and means for isolating and effectively sealing said 25 projecting writing tip member from atmosphere when said writing instrument body and cap means is as- 401-202 sembled with said cartridge means, said isolating means comprising 

